Industry utilizes or has proposed various image scanners in different applications and fields. The light source of the conventional image scanner is usually categorized in two types: CCFT (cold cathode fluorescent tube) and fluorescent lamp. After the CCFT or the fluorescent lamp is lighted up, the brightness thereof will increase gradually to then be stable after 4 or 5 minutes. Thus it is a must to warm up the conventional image scanner several minutes to obtain a more stable scanning effect. In addition, the brightness will be decreased owing to the aging of the fluorescent lamp. In today's technology, one way to solve the above-mentioned problem is to incorporate the light fibers in the image scanner, but actually it is an expensive and inconvenient expedient.
From the above it is seen that a cost effective and easily-assemblable image scanning device with a relatively stable and satisfactory scanning effect is often desired.